Simmering shutter for high-pressure metal vapor lamps



Nov. 28, 1950 J. B. s. SMYTH 2,531,924

SIMMERING SHUTTER FOR HIGH-PRESSURE METAL VAPOR LAMPS Filed Aug. '7, 1948 3 Sheets-Sheet 1 FIG. 1.

INVENT R Jom BERNARD 50RE SMYrl-l AT ORNEY Nov. 28, 1950 J. B. s. SMYTH 2,531,924

SIMMERING SHUTTER FOR HIGH-PRESSURE METAL VAPOR LAMPS Filed Aug. 7, 1948 3 Sheets-Sheet 2 l N V E N TOR FlG. 2 JOHN BmuAw5co r5 -1r -r ATTO RN 1 Nov. 28, 1950 J. B. s. SMYTH 2,531,924

SIMMERING SHUTTER FOR HIGH-PRESSURE METAL VAPOR LAMPS Filed Aug. '7, 1948 3 Sheets-Sheet 3 INVENTOR JoHN BERNARD onz SMYTH Patented Nov. 28, i950 SIMMERING SHUTTER FOR HIGH-PRES- SURE METAL VAPOR LAMPS John Bernard Score Smyth, London, England, as-- signor to The General Electric Company, Limited, London, England Application August 7, 1948, Serial No. 43,049 In Great Britain August 11, 1947 8 Claims.

This invention relates to lanterns for'lamps of the high pressure metal vapour type such, for example, as high pressure mercury vapour (HPMV) lamps and which are suitable for lighting studios and the like.

It is well known that when such lamps are switched 01f after they have been working some time must elapse before they can be made to relight unless relatively complicated means for restarting are provided. It has previously been proposed that lanterns for use with lamps of this type should be provided with movable members arranged to surround or enclose the lamp so that, when the lantern is extinguished after giving light, the current through the lamp may be reduced to a low value and the electric discharge on the lamp being maintained by the heat energy reflected from the said members. This arrangement is normally termed a simmering arrangement.

One object of the present invention is to provide a lantern having a simple simmering arrangement.

According to the present invention, a lantern, for a lamp of the high pressure metal vapour type, includes a simmering arrangement comprising two pairs of arcuate shutters arranged to enclose at least the bulb or the like of a lamp in the operating position, each pair of shutters being mounted for rotation about an axis disposed to one side of the lamp, the axes being parallel and the two shutters of each pair being arranged to rotate in opposite directions to open and close.

Preferably the axes of the two pairs of shutters are parallel to the axis of the lamp and all the shutters are arranged to be operated together by a common means.

One construction of a lantern in accordance with the invention and suitable for lighting cinema studios and the like will now be described by way of example with reference to the four figures of the accompanying drawings in which Figure 1 shows a diagrammatic section through the optical axis of the lantern, Figure 2 shows an enlarged sectional front elevation of the lamp carrier and simmering arrangements, Figure 3 shows a section at line IHIII on Figure 2 and Figure 4 is a, sectional front elevation showing part of the lamp carrier not shown in Figure '2.

Referring now to Figure l the lantern comprises a substantially cylindrical housing I for a 10 kilowatt high pressure mercury vapour lamp 2, the lamp 2 being mounted on a carrier 3 as hereinafter described. Also mounted on the carrier 3 on the side remote from the projection lens 4 is a spherical concave reflector 5. In order to spread or close the beam of lightfrom the lantern the carrier 3 is mounted on. rails 6 extending the length of the lantern and. may be moved to or from the lens 4 by rotating a handle l at the back of the lantern, the handle- 1 being connected to a screw-threaded shaft 8 which engages with a collar 36 on the carrier 3..

Electric supply terminals 9 and I0 are'provided in the back of the lantern, the negativeterminal 9 being connected to the carrier 3 by the flexible lead II and the positive terminal [0' connected through the hinged device I2.

Referring also to Figures 2 and 3, the lamp 2 is located between centres l3 and M, the bot-- tom centre [4 being fixed to the carrier and thetop centre 13 being spring-loaded and positioned by the side pillars 34 and 35. The carrier 3 alsohas mounted on it the simmering arrangement associated with the lamp 2. Thus two pairs of shafts l5 and It, and I1 and I8 are provided on the carrier 3, the two shafts of each pair being co-axial with their axes parallel to the axis of the lamp 2, the two pairs being symmetrically disposed one on either side of the lamp. Each shaft [5, I6, I? and It carries an arcuate metal.- Shutter I9, 20, 2| or 22 arranged so that when the shutters [9 to 22 are in their closed position, they just overlap one another and substantially enclose the bulb 23 of the lamp 2 in a cylindrical container. Each pair of co-axial shafts l5, l6 and I1, I8 is arranged to form, in effect, a hinge upon which the associated shutters can be turned as hereinafter described.

The co-axial shafts l5 and [6 are connected to bevel gears 24 and 25 respectively which gears engage on diametrically opposite sides of a bevel gear 26 carried on an associated shaft 27 lying parallel to the optical axis of the lantern. Thus by rotation of the associated shaft 27 the pair of shutters l9 and 2e carriedby the pair of shafts l5 and I6 move in opposite directions and are made to open or close.

In like manner movement of the shutters 2! 3 and 22 is controlled by the associated shaft 28. The two shafts 21 and 28 associated with each pair of co-axial shafts l5, l6 and I7 and I8 are mechanically linked by a transverse member 29 as shown in Figure 4 and each shaft 21 and 28 is spring-biased over a dead centre position. The shaft 28 is geared to a collar 30 which carries a double key 3! engaging with axial slots in a further shaft 32 lying parallel to the optical axis of the lantern the shaft 32 extending through the rear, of the lantern housing I and being terminated by an; operating knob or lever 33; (see Figure 1) The further shaft 32 is fixed axially relative to the lantern housing I and is slotted. to permit the carrier 3 with the lamp 2 and simmering arrangement to move .asjhereinbefore described.

When the lantern is giving light, the shutters l9 to 22 open as shown in themositions [9 to 12. in Figure 3 so that there is a substantially free optical path between the spherical reflector 5, the lamp 2 and the projectionlens lrattheyfront of the lantern. The shutters l9 to 22am so-arranged that they rotate through approximately 90 between their closed :and open positions. The gearing between the operating lever .33.and the shutters-lam; 2 2,are allot 1:1 ratioso that the shutters are opened or closed, and thus the light from thelantern controlled, by rotating the lever 33-through approximately 90. Aspreviously dethe two-shutters .of each pair in. PP r6 tions abouttheir pivot axe s into extreme closed and opengpositions, the shutters in the closed position enclosing'atleastthe part of thelamp iii-which; theelectric discharge occurs and in-the open position exposing said .part of the lamp,

-2,-A lantern including an electric discharge larnpof the high pressure metal vapour type: and a; simmeringarrangement for sa-idlamp comprisingapairof :arcuate shutters, means-pivotally supporting said shutters for rotation abouta fixed axisdisposed toone side of the lampfarsecond.

pair-of; arcuate shutters, -means :pivotally suplifi fiiing; saidqsecondipair of shutters. for: rotation thereof about. a, second fixed axis; on the -.other sideof'said lamp and parallel toandsspaced from said first-mentioned axis, and means to pivot the twoshutters of eachapair inppposite directions-about the pivotaxes into a '.closed- QOSi-e tion, inwhich-the shutters (lo-operate, together to surround-at least the part of the lamp: in which the electricdischargeoccurs Land to reflect-back into-thelamp heat energyradiated thereiromand into an open position in which the shutters expose said-part 0f the lamp.

3; 'A lantern including anelectric discharge lamp of the high pressure-metalvapouritypeeand alsimmering arrangement for-said lamp com,- prising a pair oiarcuate shutters, means pivotally supporting said shuttersfor rotationaboutafixed axissdisposed .to one sidelof the lamp, a-second pair of arcuate shutters, means pivotally supporting said second pair of shutters for rotation thereof about a second fixed axis on the other side of the lamp and parallel to and spaced from said first-mentioned axis, and a snap action mechanism to pivot the two shutters of each pair in opposite directions about their axes with a snap action into extreme closed and open positions, the shutters in the closed position co-opcrating together to surround at least a part of the lamp in which the electric discharge occurs and-ltorefiect; back into the lamp heat energy radiated therefrom, and in the open position ex- .posing said part of the lamp.

4. For use in a lantern for a lamp of the high 'pressure metal. vapour type, a simmering mechanismwcomprising two pairs of arcuate shutters, means, mounting one, pair of said shutters for .p'ivotal movement'in opposite directions about a fixedsaxis-disposedto one side of said lamp, means mounting the second pair of shutters for pivotal movement-in opposite directions about a second fixedaxis parallel to the first-mentioned axis, and actuating means for pivoting the two shutters of each pair in opposite directions about their pivotiaxes into. closedand openpositions, the shuttersinlthe closed position enclosingat least the part of the lampin which the .electricfldisr chargeoccursand operating to. reduce radiation of'heat therefrom, and in 'thelopenpositionexe posingsaid partof the lamp.

1'5..For..use .in.a.lante1in for .a lamp of thew-high pressure metal vapour. type, .a simmering mocha-- nism ..comprising two pairs of v .ancuate shutters,

rreans. vmounting one-pair .of. .said shutters for. pivotal movement .'.in opposite directions about a fixedaxis disposedto one side ofsaidilampmeans mounting the other ,pair, of..shutters .for. pivotal movement in opposite directions .abouta .second fixed axis on the other side. of .said lampand parallel.tosthefirstemeritioned.axis andamechanismforepivoting the two shutters .of .each pair in opposite, directions about-their. axes into ,a.

closed position in which ,the shutters co=operate together to surround at least the part. of thelamp in which .the electric dischargeloccursand to. re-

flect .backminto thelamp heat .energy radiated.

therefrom, and into an open positiomin ,which theshutters .expose said part .of .the lamp.

.6..Eor useinalanternsfor alamp of the high pressurelmetal vapour .type,. a simmering mechanism .compriisingtwopairs of arcuateshuttersr means rx-ioun-ting one pair .of said shuttersfor pivotal movement in. opposite directions about ahfixed ..axis.edisposed .to.one side ofsaid lamp,

- means mounting .the. other mail .ofshuttersior pivotal. movement. in opposite directions; about asecond fixedaxis on they other. side-of. saidlamp.

inthe openipositionbeing disposeduso thatithey exposesaid part of the. lamp.

7- ,A lantern, including ,an electric discharge lamp; of; the high,pr.essure metal ,vapour type, :a-

housing; meanstosupport saidlampiin sa-idhOHS- ing, said, housing 1. having; an eopem'ng through which light from-the. lamp,- is -adaptedpto be proj ected,.a:.refiector,=.means. to. mount said:refiector in said housing on the side of said lamp opposite to the side nearest the opening, and a simmering mechanism for said lamp, said simmering mechanism being inside the housing and comprising two pairs of arcuate shutters, means mounting one pair of said shutters for pivotal movement in opposite directions about a fixed axis disposed to one side of a line running from the reflector to the opening through the lamp, means mounting the second pair of shutters for pivotal movement in opposite directions about a second fixed axis parallel to the first-mentioned axis and on the opposite side of said line, and actuating means for pivoting the two shutters of each pair in opposite directions about their pivot axes into closed and open positions, the shutters in the closed position enclosing at least the part of the lamp in which the electric discharge occurs and operating to reduce radiation of heat therefrom and in the open position exposing said part of the lamp between the reflector and the opening.

8. A lantern as set forth in claim '7 wherein the actuating means for pivoting the two pairs of shutters includes a snap action mechanism to move the shutters with a snap action into extreme closed and open positions.

JOHN BERNARD SCORE SMYTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date a 537,918 Edwards Apr. 23, 1895 2,405,286 Bourne Aug. 6, 1946 FOREIGN PATENTS Number Countm Date 701,331 Germany Jan. 14, 1941 

